The present invention relates generally to electrical connectors, and, more particularly, to a key retention system for electrical connectors.
Electrical connectors are frequently provided with keying means to permit particular pairs of connectors to properly mate and to prevent the mating of connectors which are not intended to be mated. Keying means are especially useful when a plurality of identical connectors are positioned in close proximity to one another, for example, on a printed circuit board. The incorrect matching of complementary connectors to the connectors on the board can cause serious damage to the circuits improperly connected thereby; and the keying means, by ensuring that each complementary connector will mate with only the correct one of the plurality of connectors on the board, minimizes the risk of improper connection. Keying means are particularly important when the connections are made by untrained personnel as the risk of improper connection is especially great in such circumstances.
Keying systems are known in which a key member is secured in one of a pair of complementary connectors and is adapted to cooperate with an opposing key member secured in the other of the pair of connectors. Each key member is secured in its connector in a selected orientation with respect to its opposing key member so that when the connectors are intended to be mated, extended keying sections on the key members pass by each other during mating to allow the connectors to properly mate. If one of the key members is secured in an incorrect orientation with respect to its opposing key member, however, the extended keying sections on the key members will abut one another during mating to prevent proper mating of the connectors.
One known type of key member is provided with a portion having a polygonal cross-section and is adapted to be secured within a passageway in a connector in a selected orientation. The number of sides of the polygonal shape determines the number of possible orientations of the key member.
To ensure that the keying system operates reliably, it is important that the key members be accurately positioned and retained within their respective connectors with the keying sections thereof in the selected orientation. Any significant movement of a key member within its connector can prevent the proper mating of connectors which are intended to be mated, or permit the mating of connectors which are not intended to be mated. Many known keying systems, however, are not satisfactory in preventing movement of the key members.
Also, orienting of a key member and positioning and securing the key member in a connector is typically performed by hand, and, in many known keying systems is a difficult, time-consuming procedure. Orienting and securing of the key member is particularly troublesome in small connectors inasmuch as the key member also tends to be quite small and rather difficult to handle.